Due to recent increases in high performance of electronic components and density growth thereof on a control board, there is significantly increased heat generation from the control board. Also due to recent increases in downsized, densely integration in electronic components and an amount of information to be processed, various cooling methods have been invented, e.g. to effectively cool electronic components close to heated areas and to cool respective racks. (for example, PTL 1)
A conventional cooling device for rack-type electronic equipment is described hereinafter with reference to FIG. 10. As shown in FIG. 10, the conventional rack-type electronic equipment comprises a group of circuit boards 102 including electronic circuits thereon inside enclosure 101 and a cooling device including heat pipe 103 and heat exchanger 104. The group of circuit boards 102 is orderly arranged into a rack shape inside enclosure 101. Heat pipe 103 is disposed to fill a gap between each one of the groups of circuit boards 102. Heat exchanger 104 is disposed on a top of enclosure 101 and heat pipe 103 is connected to heat exchanger 104. Inlet 105 and outlet 106 are disposed at the top of enclosure 101. Air blower 107 disposed close to inlet 105 is activated to pass outdoor air through enclosure 101. An air sucked from inlet 105 is discharged from outlet 106 through heat exchanger 104.
Heat generated from the group of circuit boards 102 warms ambient air. The high-temperature air is cooled by heat exchange with refrigerant in heat pipe 103. Vaporized refrigerant by heat absorption travels upward through heat pipe 103 and moves into heat exchanger 104. The vaporized refrigerant is condensed to liquid by heat exchange with cold outdoor air sucked by air blower 107 in heat exchanger 104 and goes down through heat pipe 103.
The conventional cooling device needs to be designed as an integrated cooling device comprising enclosure 101 and the group of circuit boards 102 because heat pipe 103 is disposed to fill the gap between each one of the group of circuit boards 102. For that reason, heat pipe 103 needs to be designed in response to size and quantity of the group of circuit boards 102.
In the cooling device shown in FIG. 10, since heat pipe 103 forms a cooling cycle for the whole cooling device, it is difficult for the conventional cooling device to deal with different heat quantities generated from each one of the groups of circuit boards 102.